Machine to Machine (M2M) technology refers to any technique or method of establishing a connection among machines. The concept of M2M has appeared in the 1990s, remaining a theory, however. After the year 2000, development of mobile communication technology allows possibility of implementing machine networking by mobile communication technology. An M2M service has appeared in the market around 2002, developed rapidly in a few years thereafter, and become the focus of attention of numerous communication equipments suppliers and telecom operators. Globally, at present, the number of machines is much larger than the population, so a promising market of the M2M technology may be expected.
Study on a scenario where M2M communication applies indicates a potential market of providing M2M communication on a mobile network. However, as the M2M service raises many new requirements on a system, in order to increase the competitiveness of a mobile network in this respect, an existing mobile network has to be optimized to support M2M communication more effectively.
The existing mobile communication network is designed mainly for communication among people, and is not optimized with respect to communication among machines and communication between a machine and a human. Another key for successful layout of M2M communication is the ability of an operator to provide a service of M2M communication at a lower cost.
In view of this, it is necessary to research on a solution to supporting M2M communication by a mobile network. The solution should maximize reuse of an existing network, and reduce impact of massive M2M communication on the network as well as complexity in operation maintenance.
Presently, there is an increasing competition in a telecommunication market, with decreasing rate and profit margin of the operator. A communication market based on people is going saturated, while the M2M is a brand-new opportunity for an operator.
To utilize a mobile network resource effectively, a 3rd Generation Partnership Project (3GPP) proposes a service of Machine Type Communication (MTC) including M2M communication and Machine-to-Man communication, the scope of which service goes far beyond H2H (Human to Human) communication. MTC differs completely from the existing H2H communication in aspects such as access control, billing, security, Quality of Service (QoS), a service mode.
A 3GPP Evolved Packet System (EPS) includes a core and a radio access network, such as a UMTS Universal Terrestrial Radio Access Network (UTRAN), an Evolved UTRAN (E-UTRAN), a GSM/EDGE Radio Access Network (GERAN). An Evolved Packet Core (EPC) includes network elements such as a Mobility Management Entity (MME), a Serving Gateway (SGW), a Packet Data Network (PDN) Gateway (PGW). A GPRS core includes network elements such as a Serving GPRS Support Node (SGSN). The E-UTRAN includes an evolved Node B (eNB).
A basic requirement to an MTC system is to trigger an MTC UE (i.e., a UE serving for MTC), a focus thereof being as follows. In order to control communication of an MTC UE, a possible way to communicate is to initiate a poll by an MTC server. For communication initiated by an MTC UE, sometimes the MTC server is required to poll MTC UEs for data. If query by the MTC server fails or an IP address of an MTC UE is not available, then the MTC server may establish communication with the MTC UE by triggering the MTC UE. If a network fails to trigger an MTC UE, then the network reports to the MTC server the failure to trigger the MTC UE. MTC-UE triggering is implemented via control-plane signalling in 3GPP.
MTC-UE triggering includes Mobile Originated (MO) and Mobile Terminating (MT) services, i.e., sending or receiving information by an MTC UE.
To implement effective transmission of the trigger message, solutions proposed include sending the trigger message via a Short Message Service (SMS), via control-plane signalling, or via user-plane data. For the sending the trigger message via control-plane signalling, an MTC server sends control-plane signalling including the trigger message to an MTC InterWorking Function (MTC-IWF); the MTC-IWF selects to send the trigger message to the MTC UE through an interface T5 or T4. For the sending the trigger message via user-plane data, the MTC server sends the trigger message to the MTC-IWF; the MTC-IWF acquires an IP address of the MTC UE and sends the trigger message to the MTC UE via a user plane.
MTC architecture in 3GPP is as shown in FIG. 1, wherein on a user plane, an application on an MTC UE communicates with an MTC server via an interface API, or communicates directly with a PGW/Gateway GPRS Support Node (GGSN) in a 3GPP network via an interface Gi/SGi; the MTC server communicates with the GGSN/PGW via the interface Gi/SGi; the GGSN/PGW communicates with the MTC UE via a Radio Access Network (RAN); on a control plane, the MTC server sends control-plane signalling including trigger message to an MTC-IWF via an interface Tsp; the MTC-IWF sends the control-plane signalling to at least one of an MME, an SGSN, and a Mobile Switching Center (MSC), or to a Short Message Service Center (SMSC), and then the control-plane signalling is sent to the MTC UE via the RAN.
FIG. 2 is a schematic diagram showing that an MTC server sends the trigger message on an interface T5 via an MTC-IWF, wherein the MTC server sends control-plane signalling including the trigger message directly to the MTC-IWF via an interface Tsp; the MTC-IWF sends the trigger message to MME/SGSN/MSC via the interface T5, and then the trigger message is further sent to the MTC UE.
After receiving the trigger message, the MTC UE may communicate with the MTC server as indicated by the trigger message, such as establish a user-plane bearer, or communicate with the MTC server via an SMS.
Study and practice of related art shows that when an MTC-IWF selects to send the trigger message via an interface T5, it is not specified how the trigger message is packaged at the interface T5, and how the trigger message is sent to the MTC UE after an MME and/or SGSN and/or MSC receives the trigger message.